Gripper for a loading machine of a nuclear reactor



Jun18,1968 HNSSON ET AL 3,388,942

GRIPPER FOR A LOADING MACHINE OF A NUCLEAR REACTOR Filed May 20, 1966 Fig.1

F III 21 INVENTORS Karl Go'ran Ernst Frm n Erik Bbr 'eJohnsson ATTORNEYS United States Patent 3,388,942 GRIPPER FOR A LOADING MACHINE OF A NUCLEAR REACTOR Erik Biirje Johnsson, Stockholm, and Karl Goran Ernst Froman, Solna, Sweden, assignors to Aktiebolaget Atomenergi, Stockholm, Sweden, 21 company of Sweden Filed May 20, 1966, Ser. No. 551,785 Claims priority, application Sweden, May 24, 1965, 6,814/65 4 Claims. (Cl. 294-95) The invention is concerned with a gripper for a loading machine of a nuclear reactor. The gripper is adapted to be suspended on a wire belonging to the loading machine, and to seize the upper portion of a fuel element to lift the element out of the reactor or to lower it into the reactor. It is the object of the invention to provide a gripper, having a minimum of moving parts, which can seize and release the fuel element merely by the suspending wire being actuated.

The gripper of the invention comprises a frame having on its lower portion at least two lifting hooks which can be moved between an inoperative position and an operative position in which they engage the upper portion of a fuel element which is to be lifted out of or lowered into the reactor, and an operating member which is movable in the frame and which is secured to a wire belonging to the loading machine, the operating member engaging the frame by means of a groove and a pin to the effect that a lowering and a subsequent lifting of the operating member relative to the frame produces a rotation of the operating member by a predetermined angle relative to the frame, the operating member being provided with two sets of shoulders to engage the lifting hooks, namely a first set holding the lifting hooks in their inoperative position and a second set holding them in their operative position, the two sets of shoulders being displaced a distance corresponding to said angle.

The invention will now be explained with reference to the accompanying drawing. FIG. 1 illustrates, partly in section, a gripper of the invention having the lifting hooks in the operative position. FIG. 2 illustrates a part of the gripper, the lifting hooks being in the inoperative position. FIG. 3 illustrates a cross-section along line llllll of FIG. 1.

The illustrated gripper comprises a frame consisting of three longitudinal portions 1 which are fastened to each other by an inner tubular part 15, an outer upper ring 16 and an outer lower ring 17. The lower portion of the frame contains three horizontal axle journals supporting three lifting hooks 3. Each axle journal 5 also supports a pawl 4 having on its lower end a roller 18 and on its upper end a blocking member 19. The pawl 4 is actuated by a spring 20 urging the blocking member 19 inwardly.

A cylindrical operating member 2 extends axially through the centre of the frame. The upper portion of the operating member 2 is suspended on a wire 21 operated by the loading machine. Shoulders 24 of the frame 1 are positioned to cooperate with corresponding shoulders 25 of the operating member 2. The outer surface of the operating member 2 contains a groove defined by an upper surface 22 having the shape of saw teeth and by a lower surface 23. One or several pins 10 extend through the frame into said groove. When the operating member is lifted and lowered in the frame the groove and the pin will coact to rotate the operating member in the frame.

This will be easily understood by means of the illustrated relative positions 10a-10e of the pin 10. When the operating member is lowered the pin will move from position 3,388,942 Patented June 18, 1968 10:: into position 10c. When the operating member is now lifted the pin will move from position 10c into position 10e. Each surface 22, 23 of the groove has six teeth, and therefore a complete operating movement (lowering and lifting) will rotate the operating member 60 in the frame. For preventing a rotation of the operating member in the wrong direction the operating member has a plurality of axially extending grooves 26 engaging a spring-urged pawl 27, thus forming a ratchet wheel allowing the rotation in one direction only.

The lower end of the operating member 2 is provided with three shoulders 8. According to FIG. 1 said shoulders 8 keep the lifting hooks 3 in the operative position. On a somewhat higher level the operating member 2 is provided with three shoulders 12. According to FIG. 2 said shoulders 12 keep the lifting hooks in the inoperative position. The shoulders 12 are displaced by 60 relative to the shoulders 8. Consequently, the lifting books 3 will be in the operative position in every second position of the operating member 2, for instance when the pin 19 is in position 10a, and they will be in the inoperative position in every second position of the operating member 2, for instance when the pin 10 is in position 10c.

The outer surface of the operating member 2 contains a circumferential groove 28 engaging the blocking memher 19 of the pawl 4. In the position illustrated in FIG. 2 the operating member 2 cannot be moved in the axial direction relative to the frame 1.

When a used fuel element 6 is to be lifted out of its channel 7a, 7b the gripper is lowered into said channel, suspended on the wire 21 which is operated by the loading machine. When the gripper is a little distance above the fuel element the rollers 18 come into contact with a narrow portion 7b of the channel, resulting in the blocking members 19 leaving the groove 28. The gripper is lowered so far that the inclined surfaces 13 of the frame 1 engage an inclined surface 14 of a lifting member 9 belonging to the fuel element 6. The wire 21 is now so operated that the operating member 2 first moves downward and then moves upward in the frame 1, resulting in the operating member 2 being rotated by 60. The shoulders 8 now move the lifting hooks 3 into their operative position. When the upward movement of the operating member 2 is now continued the frame 1 will be lifted by the operating member by the shoulders 25 engaging the shoulders 24, and the lifting hooks 3 will lift the fuel element. When the rollers 18 reach the wider portion 7a of the channel the blocking members 19 will engage the groove 28, thus blocking any further movement of the operating member relative to the frame 1.

What is claimed is:

1. A gripper for a loading machine of a nuclear reactor, comprising a frame having on its lower portion at least two lifting hooks which can be moved between an inoperative position and an operative position in which they engage the upper portion of a fuel element which is to be lifted out of or lowered into the reactor, and an operating member which is movable in the frame and which is secured to a wire belonging to the loading machine, the operating member engaging the frame by means of a groove and a pin to the effect that a lowering and a subsequent lifting of the operating member relative to the frame produces a rotation of the operating member by a predetermined angle relative to the frame, the operating member being provided with two sets of shoulders to engage the lifting hooks, namely a first set holding the lifting hooks in their inoperative position and a second set holding them in their operative position, the two sets of shoulders being displaced a distance corresponding to said angle.

2. A gripper as claimed in claim 1, having three lifting 3 hooks, the operating member being adapted to rotate 60 References Cited upon being lowered and subsequently being lifted. UNITED STATES PATENTS 3. A gripper as claimed in claim 1 in which the operat- 1 ing member is provided with blocking means allowing it 8/1965 Alhot 294 116 to be rotated in one direction only relative to the frame. 5 FOREIGN PATENTS 4. A gripper as claimed in claim 1 comprising block- 1334.480 W1963 France ing means to prevent a longitudinal movement of the operating member in the frame, said blocking means GERALD M FORLENZA Primary Examiner. containing a part extending radially to be actuated by a narrow portion of the channel for the fuel element. thus M) ABRAHAM, AS31314"! releasing the operating member. 

1. A GRIPPER FOR A LOADING MACHINE OF A NUCLEAR REACTOR, COMPRISING A FRAME HAVING ON ITS LOWER PORTION AT LEAST TWO LIFTING HOOKS WHICH CAN BE MOVED BETWEEN AN INOPERATIVE POSITION AND AN OPERATIVE POSITION IN WHICH THEY ENGAGE THE UPPER PORTION OF A FUEL ELEMENT WHICH IS TO BE LIFTED OUT OF OR LOWERED INTO THE REACTOR, AND AN OPERATING MEMBER WHICH IS MOVABLE IN THE FRAME AND WHICH IS SECURED TO A WIRE BELONGING TO THE LOADING MACHINE, THE OPERATING MEMBER ENGAGING THE FRAME BY MEANS OF A GROOVE AND A PIN TO THE EFFECT THAT A LOWERING AND A SUBSEQUENT LIFTING OF THE OPERATING MEMBER RELATIVE TO THE FRAME PRODUCES A ROTATION OF THE OPERATING MEMBER BY A PREDETERMINED ANGLE RELATIVE TO THE FRAME, THE OPERATING MEMBER BEING PROVIDED WITH TWO SETS OF SHOULDERS TO ENGAGE THE LIFTING HOOKS, NAMELY A FIRST SET HOLDING THE LIFTING HOOKS IN THEIR INOPERATIVE POSITION AND A SECOND SET HOLDING THEM IN THEIR OPERATIVE POSITION, THE TWO SETS OF SHOULDERS BEING DISPLACED A DISTANCE CORRESPONDING TO SAID ANGLE. 